Electric disconnect switch having improved operating mechanism

ABSTRACT

An electric disconnect switch comprising a switch blade movable between open and close positions with respect to a relatively stationary contact means and a switch blade operating mechanism for rotational movement of the switch blade about its own axis and pivotal movement about an axis generally perpendicular to the switch blade. The switch blade operating mechanism provides for rotation of the blade about its longitudinal axis in sequence with pivotal movement of the blade about an axis perpendicular to the longitudinal axis of the switch blade with no overlap of the movement.

[ Jan. 16, 1973 United States Patent 91 Kuhn [ 1 ELECTRIC DISCONNECT SWITCH Primary Examiner-Herm'an J. Hohauser HAVING IMPROVED OPERATING Attorney-FA. T. Stratton et al. MECHANISM [75] Inventor:

7] ABSTRACT An electric disconnect switch comprising a switch Edmund W. Kuhn, Pittsburgh, Pa.

Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

blade movable between open and close positions with respect to a relatively stationary contact means and a Filed: Jan. 17, 19 switch blade operating mechanism for rotational movement of the switch blade about its own axis and 2| Appl. No.: 218,331

pivotal movement about an axis generally perpendicular to the switch blade. The switch blade operating U-Sn CL uun...u"u......n...u..........---.-....-200/48 A mechanism provides for rotation of the blade about its [51] Int. 31/00 longitudinal axis in Sequence with pivotal movement [58] F eld of Search................200/48 R, 48 SB, 48 A of the blade about an axis perpendicular to the longitudinal axis of the switch blade with no overlap of the movement.

' 8 Claims, 13 Drawing Figures 3,148,252 Bernatt...............................200/48 A PATENTEDJAH 16 ms sum 3 OF 7 wdE PATENTEDJAH 16 I975 SHEET BF 7 m oE PATENTEUJAH 16 I973 SHEET 8 [1F 7 ELECTRIC DISCONNECT SWITCH HAVING IMPROVED OPERATING MECHANISM BACKGROUND OF THE INVENTION This invention relates to electric disconnect switches and more particularly to the pivotal type structure which forms part of such switches and the operating mechanism for moving the blade between the open and close positions of such switches. Generally the pivotal blade type of disconnect switch includes a blade having one end pivotally attached to a fixed support mounted on a stationary insulating stack, and having the other end adapted for swinging motion about the pivot to a point between the spaced contact jaws of the fixed contacts, mounted upon another insulating stack, whereupon rotation of the blade about its longitudinal axis provides high pressure engagement with the fixed contact jaws. When the switch is to be opened, the blade is axially rotated to effect disconnection between the jaws and the blade, then the blade is swung to the fully open position. To effect closing of the disconnect switch, the blade is swung between the jaws and axially rotated to effect high pressure contact between the free end of the blade and the fixed contact jaws. Present designs of disconnect switches utilize mechanisms for rotary and pivotal movements of the blade which allows these movements to overlap. The movements do not occur completely sequentially, thus resulting in difficulties of operation and the need of frequent adjustment for optimum switch performance. A further disadvantage of most of the prior art disconnect switches is that during a closing operation when the switch blade is disposed between the fixed contacts and axially rotated to effect high pressure contact, there is little force holding the switch blade down to prevent pivotal movement of the switch blade. Under adverse conditions, the switch blade will climb out of the fixed contact jaws upon rotation.

SUMMARY OF THE INVENTION In accordance with the invention, an electric disconnecting switch which includes a switch blade that is movable from an open position with respect to an associated relatively stationary contact assembly through an arcuate path toward a closed position with respect to the contact assembly and which is finally rotated about its own axis to engage the contact jaws of the contact assembly, to establish adequate contact pressure between the free end of the switch blade and the contact jaws of the relatively stationary contact assembly. The switch blade is moved by an operating mechanism which completely separates the pivotal motion, when the free end of the switch blades rotates through an arcuate path about the blades pivotal end, from the rotary motion, when the switch blade is rotated about its longitudinal axis while it is disposed between the contact jaws. While the switch is being pivoted in an arcuate path about its fixed end, a switch blade locking means is engaged to prevent the blade from rotating about its longitudinal axis. When the switch is disposed between the contact jaws, a switch blade hold down means prevents the switch blade from rising or riding out of the contact jaws while the blade is being rotated about its longitudinal axis.

The switch blade operating mechanism comprises a switch blade pivoting means, for moving the switch blade between an open position and a closed position, where the free end of the switch blade is disposed between the fixedcontact jaws, and a switch blade rotating means, for rotating the switch blade about its longitudinal axis, when the free end of the blade is disposed between the contact jaws, to resiliently deflect the contact jaws. The switch blade pivoting means comprises a lifting stud, rotatable around an axis perpendicular to the axis about which the switch blade moves in an arcuate path, and a hinge member, which is attached to and supports the switch blade for movement about an axis generally perpendicular to the longitudinal axis of the switch blade. The hinge member is attached to the switch blade, for movement therewith, so as to prevent movement of the switch blade along its longitudinal axis while permitting limited rotary movement of the switch blade around its longitudinal axis. The lifting lever is rigidly attached to the hinge member, at the pivotal axis of the hinge member, so as to move the switch blade in an arcuate path when the lifting lever is rotated. A lifting pin extends from the lifting lever parallel to the axis about which the hinge member rotates, said lifting pin is engaged by the lifting stud when the lifting stud is rotated in a clockwise direction so as to raise the switch blade to a position where the free end of the switch blade is not in contact with the stationary contact means. A lowering pin extends from the lifting lever parallel to the lifting pin and is engaged by the lifting stud when the lifting stud is rotated in a counterclockwise direction so as to lower the switch blade, so that the free end is disposed between the fixed contact jaws. When the switch blade is in contact with the fixed jaws, the switch blade hold down means is positioned so that as the blade is rotated the hold down means will pass closely under the lifting pin and prevent pivotal movement of the switch blade.

The switch blade rotating means comprises a rotating stud which is rotatable around the same axis around which the lifting stud rotates and a rotating arm which is generally L-shaped and is attached to the switch blade. To effect closing of the switch, when the switch blade is disposed between the fixed contact jaws, the rotating stud is rotated in a counterclockwise direction, said rotating stud engages the rotating arm which is attached to the switch blade and rotates the free end of the switch blade into high pressure engagement with the fixed contact jaws. When the switch blade has properly engaged the fixed contacts, a stopping means prevents further counterclockwise rotation of the rotating stud. When the switch blade is rotated into proper engagement with the fixed contact jaws, a springloaded locking or indexing pin engages a slot in the hinge member to prevent further rotation of the switch blade.

To open the switch the rotating stud is moved in a clockwise direction. The rotating stud engages the rotating arm which is fixed to the switch blade and this causes the switch blade to rotate about its longitudinal axis approximately 30 so that the switch blade is disengaged from high pressure contact with the fixed contacts. When the switch blade is in this disengaged position, the spring-loaded indexing pins engage a slot in the hinge member to prevent further rotation of the switch blade. The lifting stud is then rotated in a clockwise direction into contact with the lifting pin which extends from the lifting lever attached to the hinge member. Further clockwise rotation of the lifting stud causes the hinge member to rotate about its pivotal axis thus lifting the switch blade from the fixed contact to a position displaced approximately 90 from the closed position.

In one preferred embodiment the switch blade operating mechanism is used on a disconnect switch which has a rear blade extension with inverted external hinge end contacts and an overhead counter balance system. In another preferred embodiment, the switch blade operating mechanism is used on a disconnect switch using internal hinge contacts in the blade and hinge casting with a counter balance linkage as disclosed in detail in U.S. Pat. No. 3,079,474 issued Feb. 26, 1963 to E.F. Beach et al and which is assigned to the same assignee as the present application.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is an isometric view partly in section of a portion of a disconnect switch structure embodying the principal features of the invention;

FIG. 2 is a side elevation view of a disconnecting switch structure embodying the principal features of the invention;

FIG. 3 is a top plan view of the disconnecting switch shown in FIG. 2;

FIG. 4 is an enlarged view, partly in side elevation and partly in section, of a portion of the switch structure shown in FIG. 2;

FIG. 5 is an enlarged view, partly in side elevation and partly in section, of a portion of the switch shown in FIG. 2, with the switch in the open position;

FIG. 6 is an end view of the portion of the switch shown in FIG. 4;

FIG. 7 is an end view of the same portion of the switch shown in FIG. 6, but with the switch blade rotated 30 so as to effect disengagement of the switch blade from the fixed contacts;

FIG. 8 is a top view partly in section of a portion of FIG. 2 with the switch blade in the closed position;

FIG. 9 is a top view, partly in section, of a portion of FIG. 2 with the switch blade rotated approximately 30 so as to not be in high pressure engagement with the fixed contacts;

FIG. 10 is a top view, partly in section, ofa portion of FIG. 2 with the switch in the open position;

FIG. 11 is a view, partly in section, of a portion of the switch shown in FIG. 3 along the line XIXI;

FIG. 12 is a view in side elevation, partially in section, of a portion of a disconnect switch, with internal hinge contact in the blade and hinge casting and with a bottom counter balance linkage, embodying the principal features of the invention; and

FIG. 13 is a section of the switch shown in FIG. 4 along the line XIII-XIII.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and FIGS. 2 and 3 in particular there is shown a disconnecting switch assembly 16 which comprises three spaced insulator stacks 18, 20 and 22 mounted upon a common base support 24. The base 24 is preferably a metal channel having flanges which extend outwardly from the sides of the channel. Each of the insulator stacks 18, 20 and 22 comprise a plurality of insulators which are preferably formed from porcelain or similar material. The number of insulators required in each of the stacks 18, 20 and 22 depends upon the voltage of the system in which the disconnecting switch 16 is applied. The insulator stacks 18 and 22 are mounted upon fixed pedastals or spacers 26 and 27, respectively, which are secured to the top of the base 24. The insulator stack 20 is mounted upon a shaft 28 the lower end of which is rotatably mounted in a bearing 30 which is secured to the base 24. An operating lever or crank arm 32 may be secured to the shaft 28 to rotate the insulator stack 20 during the operation of the disconnecting switch 16 as will be explained hereinafter.

The disconnecting switch 16 includes a main stationary contact assembly or break jaw assembly 34 which is mounted on and secured to the top of the insulator stack 18 as shown in FIGS. 2 and 3. The stationary contact assembly 34 includes a pair of spaced contact jaws 36 which are interconnected by a base portion that is secured to the top of the insulator stack 18 by a suitable means such as bolts. A terminal pad 38 which is adapted to receive a terminal connector is also secured to the top of the insulator stack 18 and includes a vertical extension 40 which acts as a stop for the movement of the associated switch blade 42. In addition a stationary arcing horn 43 may also be secured to the top of the insulator stack 18 as shown in FIGS. 2 and 3. The contact jaws 36 are preferably formed from a suitable material which combines relatively high electrical conductivity with excellent spring characteristics such as zirconium copper or cadmium chrome copper. The contact jaws 36 are of the reverse loop type which are used primarily to increase contact pressure when the disconnecting switch 16 is subjected to high momentary currents. Contact jaws 36 of the reverse loop type have the secondary characteristic of magnetically forcing the associated switch blade 42 downward between the contact jaws 36, in the direction towards the base portion which interconnects the contact jaws 36 and against the blade stop 40 when a relatively high momentary current flows through the disconnecting switch 16.

As can best be seen in FIGS. 4 and 11 the disconnecting switch 16 includes a plurality of stationary generally U-shaped contacts 44 which are mounted to the hinge support casting 46 by suitable means such as bolts. When the disconnect switch 16 is in the closed position, a rear extension 48 of the switch blade 42 is in high pressure contact with the generally U-shaped contacts 44. To increase the contact pressure, between the rear extension 48 and the contacts 44, biasing springs 50 may be installed between the contacts 44 and the hinge support casting 46. The rear extension 48 is rigidly attached to or an integral part of the switch blade 42, so that when the switch blade 42 is rotated around its longitudinal axis the rear extension 48 is also rotated. During an opening sequence when the switch blade extension 48 is rotated around its longitudinal axis it disengages from high pressure contact with the U-shaped rear contacts 44.

In order to provide an electrically conducting path between the hinge support member 46, which is preferably formed from aluminum in order to reduce the weight of the electrically conducting parts of the disconnecting switch 16, and the terminal end casting or member 52, a generally tubular electrically conducting member 54 structurally and electrically connects the hinge support member 46 and the terminal end member 52. The hinge support member 46 includes a flange portion 47 having an opening therein which is adapted to receive the left end of the electrically conducting member 54. The left end of the tubular conducting member 54 is secured to the flange portion 47 by a suitable means, such as welding. The terminal end member 52 includes a tubular portion 57 which is adapted so that the right end of the conducting member 54 passes therethrough. The right end of the conducting member 54 is secured to the tubular portion 57 by any suitable means, such as welding.

The electrically conducting member 54 also serves as a housing for a counter balancing mechanism or means 56. In order to assist the operating mechanism 80 in moving the switch blade 42 from the horizontal closed position to the vertical open position the counter balance mechanism 56 comprises a coil spring 58, compressible to oppose the weight of the blade 42 when in a position other than the vertical. The coil spring 58 is positioned within the previously mentioned conducting tube 54 and extends longitudinally in the tube, with one end of said spring 58 abutting the end of the tube 54 where the tube 54 is attached to the hinge support casting 46, and with the other end of the spring 58 abutting the spring guide member 60. The spring guide member 60 is positioned across the tube 54 and operable for movement along the length of the tube 54 by means of rollers 62 which are fastened at intervals around the edge of the guide member 60 by any suitable means. The rollers 62 engage the inner periphery of the tube 54 so as to prevent binding between the guide member 60 and the inner walls of the conducting tube 54, when the guide member 60 travels the length of the tube 54 during the operation of the disconnect switch 16. The force of the spring 58 is transmitted to a hinge casting 64, which is attached to the switch blade 42 to allow rotation of the blade 42 around its longitudinal axis while restraining any movement of the blade 42 along its longitudinal axis, by means of a link 66. The link 66 is pivotally attached at the one end by a suitable means, such as a pin 67, to the central portion of the guide member 60 and pivotally attached at the other end to the hinge casting 64 by a suitable means, such as a pin 68 extending through suitable openings 70 in one end of a pair of spaced flange members 72. The flange members 72 extend outward from the hinge casting 64 and extend away from the pivot point as established by pivot pins 74 to thus comprise a lever arm determined by the distance from pin 68 to a line connecting the center points of pivot pins 74. lt is to be observed that in the counter balancing mechanism 56 the force of the spring multiplied by the lever arm is approximately equal to the gravity force acting on the blade 42, and the operating mechanism 80 which tend to move the hinge casting 64 about the pivot pins 74.

In order to provide for counter balancing of the switch blade 42 when the disconnect switch 16 is vertically mounted the counter balancing mechanism 56 is used with the component parts rearranged to compensate for the effects of gravity. Specifically, the spring 58 is now arranged for compression between the stop member 76 and the guide member 60, in a reverse position, so that spring 56 provides its maximum counter balancing force when the blade 42 is opened and the minimum force when the blade 42 is closed. By providing a different length and a different spring 58 design the disconnect switch 16 may be converted from horizontal to inverted mounting. This adaptability permits the stocking of fewer parts with lower inventory costs and permits rapid assembly of switches 16 to meet the various customer requirements.

The end casting 52, which is attached to the insulator stack 22 and the conducting tube 54, has a generally U- shaped portion 78 for the terminal pad. The U-shaped terminal pad 78 can best be seen in FIGS. 4 and 13. This U-shaped terminal pad 78 facilitates attaching terminal connections to the disconnect switch 16.

When the switch 16, as best seen in FIGS. 2 and 3, is in the closed position and connected in the circuit the current flow path is in the terminal pad 38, through the contact jaws 36, into the switch blade 42, through the switch blade rear extension 48, through the rear contacts 44, into the hinge support member 46, through the conducting tube 54, into the end casting 52, and out the U-shaped terminal pad 78.

In operating the switch 16 from the closed position, as shown in FIG. 4, to the open position, as can best be seen in FIG. 5, the operating mechanism 80, as can best be seen in FIG. 1, first rotates the switch blade 42 about its longitudinal axis, this disengages the switch blade 42 from high pressure contact with the stationary contact assembly 36 and also disengages the rear switch blade extension 48 from high pressure contact with the rear contact 44, then the switch blade 42 is raised approximately around pivot pins 74. To close the switch 16 this operating sequence is reversed.

The operating mechanism 80, as can best be seen in FIG. 1, comprises a base place 82, a stop 84, a hinge casting 64 and a rotatable arm 86. The base plate 82 is firmly attached to the rotatable insulator 20 by a suitable means such as bolts 88. When the lever 32 is rotated, the rotatable insulator 20 and the base plate 82 also rotate. Extending upward from the base plate 82 parallel to the longitudinal axis of the rotatable bushing 20 are a lifting stud 90 and a rotating stud 92. As shown in FIGS. 1 and 4, when the switch 16 is in the completely closed position, the rotating stud 92 is in engagement with the rotatable arm 86, and a portion of the base plate 82 is in contact with the stop 84 to prevent further counterclockwise rotation of the base plate 82. The rotatable arm 86 is secured to the switch blade 42 for movement therewith by suitable means, such as welding or bolting. When the disconnecting switch 16 is in the closed position, the spring-loaded pins 94 in the rotatable arm 86 engage slots 96 in the hinge casting 64 to prevent undesirable rotary movement of the switch blade 42.

Starting from the closed position, when the switch 16 is to be opened the base plate 82 is rotated in the clockwise direction. Stud 92 is in loose engagement with a U-shaped portion 98. As the base plate 82 rotates the rotatable stud 92 further engages the U- shaped portion 98 of the rotatable arm 86 and causes the arm to rotate approximately 30. Rotation of the rotatable arm 86 which is firmly attached to the switch blade 42 causes the switch blade 42 to rotate around its longitudinal axis approximately 30. This first opening movement of the switch blade 42 is most clearly seen by referring first to FIG. 6, which shows the switch 16 in the fully closed position, and then to FIG. 7, which shows the switch blade 42 rotated approximately 30 around its longitudinal axis. This rotation of the switch blade 42 causes the free end of the switch blade 42 to break high pressure engagement with stationary contact jaws 36 and also causes the rear extension 48 of the switch blade 42 to break high pressure engagement with the rear contacts 44. When the switch blade 42 is in its rotated position as shown in FIG. 7, the springloaded pins 94 engage slots 100 in the hinge casting 64 to prevent further rotational movement of the switch blade 42. The initial opening movement of the rotating stud 92 and the U-shaped portion 98 of the rotatable arm 86 is further illustrated in FIG. 8, which shows a portion of the switch 16 in a completely closed position, and FIG. 9, which shows a portion of the switch 16 after the switch blade 42 has been rotated approximately 30 around its longitudinal axis, at which point the rotation of the switch blade 42, about its longitudinal axis is complete. Continued clockwise rotation of the base plate 82 will cause the switch blade 42 to be pivoted around the axis formed by the pivot pins 74.

The hinge member 64 is secured to switch blade 42 by a suitable means to prevent movement of the switch blade 42 along its longitudinal axis while still permitting limited rotation of the switch blade 42 around its longitudinal axis. A pair of substantially parallel integral bridge members 102 extend from the hinge casting 64 and are rotatably attached to the hinge support casting 46 by pivot pins 74.

During an opening operation, the switch blade 42 is pivoted about the pivot pins 74 to a position approximately 90 displaced from the closed position of the switch blade 42. A portion of the hinge member 64 extends to the rear of the pivotal axis, around the pivot pins 74, and forms a lifting lever arm 104. As the lifting lever arm 104 is rotated, the hinge member 64 and the switch blade 42 move in an arcuate path about the pivot axis formed by the pivot pins 74. Extending from the lifting arm 104 parallel to the pivotal axis of the hinge member 64 are a lifting pin 106 and a lowering pin 108. When the switch 16 is in the position as shown in FIGS. 7 and 9 with the switch blade 42 rotated around its longitudinal axis, approximately 30 from the closed position, the lifting stud 90 is in contact with the lifting pin 106 and further clockwise rotation of the base plate 82 will cause the lifting lever arm 104, the hinge member 64 and the switch blade 42 to be pivotally rotated about the axis formed by the pivot pins 74. When the base plate 82 is fully rotated in the clockwise direction, as shown in FIGS. and 10, a portion of the base plate 82, from which the rotating stud 92 extends, contacts the stop 84 and further clockwise rotation of the base plate 82 is not possible. The switch 16 is now in the fully opened position. With the switch 16 in the fully opened position, as shown in FIG. 5, the switch blade 42 is displaced approximately 90 from the switch blade 42 position when the switch 16 is in the closed position as shown in FIG. 2.

To close the switch 16, the operating lever 32, which is rigidly attached to the rotatable bushing 20 through the shaft 28, is rotated in the counterclockwise direction; this causes the base plate 82 to rotate in the counterclockwise direction. As can be seen in FIGS. 5 and 10, when the switch 16 is fully opened and the base plate 82 is rotatedin a counterclockwise direction, the lifting stud comes in contact with the lowering pin 108, which extends from the lifting lever arm 104, and moves the switch blade 42 in an arcuate path about the hinge casting 64 pivot point, formed by the pivot pins 74. As the base plate 82 is further rotated in a counterclockwise direction, the switch blade 42 moves through an arcuate path until the free end of the switch blade 42 is disposed between the fixed contact jaws 36 and the lifting stud 90 is no longer in contact with the lowering pin 108, as shown in FIGS. 7 and 9. As further counterclockwise rotation of the base plate 82 continues, the rotating stud 92 engages the U-shaped portion 98 of the rotatable arm 86 and causes the switch blade 42 to rotate about its longitudinal axis, so that the free end of the switch blade 42 is in high pressure contact with the fixed contact jaws 36 and the switch blade extension 48 is in high pressure contact with the rear contact 44.

While the switch blade 42 is rotated around its longitudinal axis the switch blade hold down means prevents the switch blade 42 from moving about the pivotal axis formed by the pivot pins 74. The switch blade hold down means 110 I comprises an extended portion 112 of the base plate 82 from which extends, parallel to the lifting stud, a curved portion 114 with a flat top 116 which rides closely under the lifting pin 106 as the switch blade 42 is rotated around its longitudinal axis. As can best be seen in FIGS. 1 and 4, the flat surface 116 being in close proximity to the lifting pin 106 prevents pivotal movement of the switch blade 42 while the blade 42 is rotated around its longitudinal axis. When the switch 16 is in the fully closed position, the extended portion 112 of the base plate 82 is in contact with the stop 84,'this prevents further counterclockwise rotation of the switch 42. The stop 84 can be attached to, or an integral part of, the hinge support casting 46.

As shown in FIG. 11, the hinge support member 46 is stabilized on top of the base plate 82 by an internally threaded bushing 116 which fits onto the threaded stud 118. The bearing portion 120 of the base plate 82 and the outer diameter 122 of the internally threaded bushing 116, against which the hinge support casting 46 might rub during rotation of the base plate 82, may be coated with a material having a low coefficient of friction, such as polytetrafluoroethylene, to facilitate rotation of the base plate 82. The outer diameter of the bearing end 124 of the pivot pins 74, which rests on the hinge support casting 46, may be coated with a material having a low coefficient of friction, such as polytetrafluoroethylene, so that the hinge casting 64 and the switch blade 42 can be easily rotated about the axis formed by the pivot pins 74.

FIG. 12 shows the invention on a portion of a disconnect switch 16 which has internal contacts and a bottom attached counter balance system 56. In order to facilitate the moving of the switch blade 42, from the horizontal closed position to the vertical opened position, the counter balancing mechanism 56 comprises a coil spring 58, compressible to oppose the weight of the blade 42 when positioned other than in the vertical. Coil spring 58 is positioned within the conducting tube 54 and extends longitudinally in the tube 54 with one end of the spring 58 abutting the tube end stop 76, away from the hinge support casting 126, and with the other end abutting spring guide member 60. The force of the spring 58 is transmitted to the hinge casting 128 by means of a link 66, pivotally attached at one end by suitable pin means 67 to the central portion of the guide member 60 and pivotally attached at the other end to the hinge casting 128 by means of a pin 68. Counter balancing the switch blade 42 when the disconnect switch 16 is vertically mountedcan be accomplished with the counter balance mechanism 56 if the component parts are rearranged to provide a force off setting the gravitational force on the blade 42. Specifically, the coil spring 58 is now arranged for compression between the stop member 130 and the guide member 60, in a reverse position, so that the spring 58 provides its maximum counter balancing force when the blade 42 is opened and the minimum force when the blade 42 is closed. For a more detailed description of this counter balancing mechanism see U.S. Pat. No. 3,079,474 issued Feb. 26, 1963 to E. F. Beach et al., and assigned to the same assignee as the present application.

The hinge member 128 is attached to the switch blade 42 so as to prevent movement of the switch blade 42 along its longitudinal axis while still permitting limited rotational movement of the switch blade 42 around its longitudinal axis. The continuous current path is maintained between the movable switch blade 42 and the fixed hinge support casting 126 by any suitable means well known in the art, such as a flexible shunt or an internal electrically conducting hinge structure as taught in U. S. Pat. No. 3,500,006 issued Mar. 10, 1970 to E. W. Kuhn and assigned to the same assignee as the present application.

The operation of the operating mechanism 80 is the same as that of the electric disconnect switch 16 having external rear contacts 44 as described above. Going from the closed position to the opened position, as the base plate 82 is rotated in a clockwise direction the rotating stud 92 engages the U-shaped portion 98 of the rotatable arm 86 and rotates the switch blade 42 around its longitudinal axis approximately 30. At this point, spring-loaded indexing pins 94 engage slots in the hinge casting 128 to prevent further rotation of the switch blade 42. The lifting stud 90 then contacts the lifting pin 106 and pivots the switch blade 42 in an arcuate path around the axis formed by the pivot pins 74, until the portion of the base plate 82 from which the rotating stud 92 extends comes into contact with the stop 84 and further clockwise rotation of the base plate 82 is not possible.

Going from the fully opened position to the closed position, the base plate 82 is rotated in the counterclockwise direction, the lifting stud 90 contacts the lowering pin 108 and moves the switch blade 42 in an arcuate path until the free end of the switch blade 42 is disposed between the fixed contact jaws 36 of the stationary contact assembly 34. At this point, the U- shaped portion 98 of the rotatable arm 86 is engaged by the rotatable stud 92 and the switch blade 42 is rotated about its longitudinal axis, so that the free end of the switch blade 42 comes into high pressure contact with the fixed contact jaws 36. Further counterclockwise rotation of the base plate 82 is not possible when the extended portion 112 of the base plate 82 comes in contact with the stop 84.

The apparatus embodying the teaching of this invention has several advantages. For example, the rotary movement and the pivotal movement of the switch blade 42 occur sequentially, without any overlap of these motions, this results in optimum switch 16 performances, without the need for frequent adjustment of the operating mechanism 80. Another advantage of the present invention, is that the switch blade hold down means 110, positively prevents pivotal movement of the switch blade 42 while it is rotated around its longitudinal axis.

Since numerous changes may be made in the abovedescribed apparatus and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all the matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

lclaim:

1. An electric switch comprising relatively stationary contact means including a pair of spaced contact jaws, formed from resilient conducting material and having substantially aligned openings extending therethrough, a longitudinal switch blade of electrically conducting material rotatable around its own longitudinal axis and movable in an arcuate path about an axis spaced from said contact means, a rotating stud rotatable around an axis perpendicular to the axis about which said switch blade moves in an arcuate path, a rotatable arm attached to said switch blade and extending perpendicular to the longitudinal axis of said switch blade so that when said switch blade is disposed between said contact jaws said rotating stud engages said rotatable arm and rotation of said rotatable stud around an axis perpendicular to the axis about which said switch blade moves in an arcuate path will cause said switch blade to be rotated around its longitudinal axis into high pressure engagement with said stationary contact means, switch blade lifting means to move said switch blade between a first position in which the free end of said switch blade is separated from said contact means and a second position in which the free end of said switch blade is disposed between said fixed contact jaws, and switch blade locking means to prevent said switch blade from moving about its longitudinal axis when said switch blade is separated from said fixed contact means.

2. The combination as claimed in claim 1 wherein said switch blade lifting means comprises a lifting stud rotatable around an axis perpendicular to the axis about which said switch blade moves in an arcuate path, hinge means rotatable about an axis perpendicular to the longitudinal axis of said switch blade and attached to said switch blade to prevent movement of said switch blade along its longitudinal axis while permitting rotational movement of said switch blade around its longitudinal axis, lifting lever means which is rigidly attached to said hinge member at the axis about which said hinge means rotates and which is displaced from the longitudinal axis of said switch blade at an angle of substantially 225, lifting pin means which extends from said lifting level parallel to the axis about which said switch blade moves in an arcuate path and which is engaged by said lifting stud when said lifting stud is rotated in a clockwise direction so as to raise said switch blade to a position where the free end of said switch blade is not in contact with said stationary contact means, and lowering pin means which extends from said lifting level parallel to said lifting pin and which is engaged by said lifting stud when said lifting stud is rotated in a clockwise direction to lower said switch blade so that the free end of said switch blade is disposed between said fixed contact jaws,

307 The combination as claimed in claim 2 wherein said lifting level means is an integral part of said hinge member.

4. The combination as claimed in claim 2 wherein said switch blade locking means comprises springloaded pin means which engages a slot in said hinge member so as to prevent movement of said switch blade around its longitudinal axis when said switch blade is separated from said contact means.

5. The combination as claimed in claim 2 wherein switch blade hold down means which prevents pivotal movement of said switch blade in an arcuate path about an axis spaced from said contact means while said switch blade is being rotated around its longitudinal axis.

6. The combination as claimed in claim 5 wherein said switch blade hold down means comprises a flat surface rotatable with said lifting stud, said flat surface moving under and in close proximity to said lifting pin while said switch blade is being rotated around its longitudinal axis to prevent pivotal movement of said switch blade.

7. The combination as claimed in claim 1 including stop means for lifting means when said switch is in the fully opened position and stop means for said rotating stud when said switch is in the fully closed position.

8. The combination as claimed in claim 7 wherein said stop means consist of a curved metal piece rigidly attached to a non-moving portion of said switch, said curved metal piece being positioned so that when said switch is fully opened a portion of said switch which is integral with said lifting stud contacts said curved metal piece and prevents further clockwise rotation of said lifting stud, and when said switch is in the fully closed position a portion of said switch integral with said rotating stud contacts the curved metal stop and prevents further counterclockwise rotation of said rotating stud. 

1. An electric switch comprising relatively stationary contact means including a pair of spaced contact jaws, formed from resilient conducting material and having substantially aligned openings extending therethrough, a longitudinal switch blade of electrically conducting material rotatable around its own longitudinal axis and movable in an arcuate path about an axis spaced from said contact means, a rotating stud rotatable around an axis perpendicular to the axis about which said switch blade moves in an arcuate path, a rotatable arm attached to said switch blade and extending perpendicular to the longitudinal axis of said switch blade so that when said switch blade is disposed between said contact jaws said rotating stud engages said rotatable arm and rotation of said rotatable stud around an axis perpendicular to the axis about which said switch blade moves in an arcuate path will cause said switch blade to be rotated around its longitudinal axis into high pressure engagement with said stationary contact means, switch blade lifting means to move said switch blade between a first position in which the free end of said switch blade is separated from said contact means and a second position in which the free end of said switch blade is disposed between said fixed contact jaws, and switch blade locking means to prevent said switch blade from moving about its longitudinal axis when said switch blade is separated from said fixed contact means.
 2. The combination as claimed in claim 1 wherein said switch blade lifting means comprises a lifting stud rotatable around an axis perpendicular to the axis about which said switch blade moves in an arcuate path, hinge means rotatable about an axis perpendicular to the longitudinal axis of said switch blade and attached to said switch blade to prevent movement of said switch blade along its longitudinal axis while permitting rotational movement of said switch blade around its longitudinal axis, lifting lever means which is rigidly attached to said hinge member at the axis about which said hinge means rotates and which is displaced from the longitudinal axis of said switch blade at an angle of substantially 225*, lifting pin means which extends from said lifting level parallel to the axis about which said switch blade moves in an arcuate path and which is engaged by said lifting stud when said lifting stud is rotated in a clockwise direction so as to raise said switch blade to a position where the free end of said switch blade is not in contact with said stationary contact means, and lowering pin means which extends from said lifting level parallel to said lifting pin and which is engaged by said lifting stud when said lifting stud is rotated in a clockwise direction to lower said switch blade so that the free end of said switch blade is disposed between said fixed contact jaws.
 3. The combination as claimed in claim 2 wherein said lifting level means is an integral part of said hinge member.
 4. The combination as claimed in claim 2 wherein said switch blade locking means comprises spring-loaded pin means which engages a slot in said hinge meMber so as to prevent movement of said switch blade around its longitudinal axis when said switch blade is separated from said contact means.
 5. The combination as claimed in claim 2 wherein switch blade hold down means which prevents pivotal movement of said switch blade in an arcuate path about an axis spaced from said contact means while said switch blade is being rotated around its longitudinal axis.
 6. The combination as claimed in claim 5 wherein said switch blade hold down means comprises a flat surface rotatable with said lifting stud, said flat surface moving under and in close proximity to said lifting pin while said switch blade is being rotated around its longitudinal axis to prevent pivotal movement of said switch blade.
 7. The combination as claimed in claim 1 including stop means for lifting means when said switch is in the fully opened position and stop means for said rotating stud when said switch is in the fully closed position.
 8. The combination as claimed in claim 7 wherein said stop means consist of a curved metal piece rigidly attached to a non-moving portion of said switch, said curved metal piece being positioned so that when said switch is fully opened a portion of said switch which is integral with said lifting stud contacts said curved metal piece and prevents further clockwise rotation of said lifting stud, and when said switch is in the fully closed position a portion of said switch integral with said rotating stud contacts the curved metal stop and prevents further counterclockwise rotation of said rotating stud. 